1. Field of the Invention
The present invention relates to a battery pack for an electric power tool that is detachably mounted on a tool body of the electric power tool as a power source for the electric power tool.
2. Description of the Related Art
A battery pack for an electric power tool, which is detachably mounted on a tool body as a power source, has been used in electric power tools. A user can conveniently use an electric power tool when the battery pack for the electric power tool is mounted on the tool body. The battery pack for an electric power tool generally includes a case that serves as a housing as well as forming an outer package, and a battery body that is provided in the case. The case is generally formed by combining an upper and a lower case. Further, the battery body includes a plurality of battery cells that can be charged and discharged and a circuit board that controls the charging and discharging of the plurality of battery cells. The plurality of battery cells are generally held in the case by a support structure that is called a cell holder (for example, refer to Japanese Laid-Open Patent Publication No. 2008-10315). One end of an electrode member is connected to an electrode of the battery cell, which is held by the cell holder, typically using welding or the like. Current is allowed to flow via the electrode members. The opposite end of the electrode member is connected to the circuit board, which is supported by the cell holder, typically using welding or the like.
The above-mentioned cell holder is assembled into the case and disposed in the case. For this reason, a clearance, which is required for disposition and assembling, is needed between the inside of the case and the cell holder.
On the other hand, the clearance formed for this purpose generates rattling of the cell holder in the case. The rattling of the cell holder may cause the movement of the battery cells to be different from that the electrode members connected to the electrodes of the battery cells. The above movement needs to be reduced as much as possible so as not to apply a load to the above-connected areas.